Oscillatory Bursts in the Optic Tectum of Birds Represent Re-Entrant Signals from the Nucleus Isthmi Pars Parvocellularis

• DOI: 10.1523/jneurosci.1379-05.2005
• Publication Date: 2005-07-27T20:13:43Z
• Authors: Gonzalo Marín; Jorge Mpdozis; Elisa Sentis; Tomás Ossandón; Juan Carlos Letelier
• Keywords: Tectum; Bursting; Biocytin; Optic tectum

Fast oscillatory bursts (OBs; 500-600 Hz) are the most prominent response to visual stimulation in optic tectum of birds. To investigate neural mechanisms generating tectal OBs, we compared local recordings OBs with simultaneous intracellular and extracellular single-unit anesthetized pigeons. We found a specific population units that responded burst discharges mirrored pattern OBs. Intracellular filling biocytin some these bursting demonstrated they corresponded paintbrush axon terminals from nucleus isthmi pars parvocellularis (Ipc). Direct Ipc confirmed high correlation between cell firing After injecting micro-drops lidocaine Ipc, corresponding locus disappeared completely. These results identify as elements presumably cholinergic ramify across layers columnar manner. Because reciprocally connected such each neuron sends part which its inputs come, represent re-entrant signals spatial-temporal is mirror representation neurons Ipc. propose an active location may act, via paintbrushes tectum, focal “beam attention” layers, enhancing saliency stimuli space.